Analysis of the treatment outcome of ampulla of Vater carcinoma and the usefulness of postoperative adjuvant chemotherapy.

692 Background: Patients with ampulla of Vater carcinoma with lymph node metastasis reportedly have a poor prognosis and require postoperative adjuvant therapy. However, due to the small number of published cases, the efficacy of postoperative adjuvant therapy has not yet been established with a high level of evidence. Objective: The aim of this study was to describe the outcome of patients surgically treated for ampulla of Vater carcinoma in our department, evaluate the effectiveness of adjuvant chemotherapy (AC), and clarify which patient groups may benefit from AC. Methods: The study cohort comprised 46 patients who underwent surgery for ampulla of Vater carcinoma in our department from October 2005 to March 2022. We evaluated the clinicopathological background characteristics (tumor size, gross morphology, pancreatic/duodenal invasion, peripancreatic head lymph node metastasis), overall survival (OS), and relapse-free survival (RFS), and compared the OS and RFS in patients with versus without AC. We then analyzed the factors related to the long-term outcome of patients treated for ampulla of Vater carcinoma. Results: During a median observation period of 33.7 months, the 5-year OS and RFS were 63.1% and 61.7%, respectively. Recurrence was observed in 14 patients (30%), with recurrence occurring less than 1 year postoperatively in seven patients (15%). Fifteen patients received AC (chemotherapy regimen: S-1 in 11 patients, GEM in four). The 5-year OS rates with and without AC were 70.3% and 48.2%, respectively (p=0.093). The 5-year RFS rates with and without AC were 72.5% and 42.8%, respectively (p=0.058). Univariate analysis of the total patient cohort showed that the factors related to 5-year RFS were pancreatic invasion (p=0.01), duodenal invasion (p=0.03), and N+ (p=0.004). In multivariate analysis, the only factor related to 5-year RFS was N+ (HR 3.53; 95% CI, 0.99–12.6; p=0.03). The 5-year OS rates in patients with and without N+ were 77.1% and 42.7%, respectively (p=0.04). The 5-year RFS rates in patients with and without N+ were 80.4% and 32.1%, respectively (p=0.004). Conclusions: AC showed a tendency to be effective in preventing postoperative recurrence of ampulla of Vater carcinoma. AC may be particularly beneficial in N+ cases.